Loud-speaker construction



Aug. 23, 1932. J. SWALLOW 1,873,360

LOUD SPEAKER CONSTRUCTION Filed June 15, 1929 7 Q9?) van far &5 d osep/z510a (Ivar M. 153% V Patented Aug. 23, 1932 UNITED; STATES JOSEPHSWALLOW, on BnnwYn, 'rnninols,

ssmme To 5113mm eonnonn'rrom .1

CHICAGO, ILLINOISfA ooRroa'ArIoN on DE AWARE IiO UD- SBEAKER Applicationfiled. June 15,

My. invention relatesbroadly to loud speakers, and has among its otherobjects the production of devices of the kind described that areeificient,durable, compact and simple in construction. V U I v Aparticular object of the invention. is to: provide improved means forsupporting the diaphragm of'aloud speaker.

Another particular object ofthe invention is to provide improved meansfor support. ing a movable armature or winding in a loud speaker, thearmature or winding being one subjected to telephonic currents andopera. tively connected to a diaphragm.

Still another particular object of the 1nvention is to provide animproved magnetizing structure for loud speakers.

A preferred form of the invention is embodied in a loud speaker whichcomprises a magnetizingstructure fabricated from parts securely held inalinement "and formedto provide an annular magnetic field in which awinding is disposed, the winding being sub j ected to telephoniccurrents delivered to it '25 from a radio-receivingset, or the like'.The winding is preferably-supported, upon an annular member secured toafldiaphragm and a rod projecting through the magnetizing structuresupports the winding, the annular 80 member and the diaphragm. The rodis supported by spaced spiral spr ng members which exert sufficienttension upon the dia phragm and the winding to hold them in their normalpositions, as shown in the draw-. ing, when the winding is not beingsubjectedto telephonic currents.

Many other objects and advantages will appear as this descriptionprogresses, reference being had to the accompanying draw ing, wherein: Vr j j V Figure 1 is a central section taken through a loud speakerembodying my. invention, and 1 i Fig. 2 is a front elevation of a spiralspring member which forms part of the loud speaker shown in Fig. 1. j 7

Referring for the present to Fig. l wherein I have shown a loud speakerembodying a preferred form of the invention, the ref- 50 erencecharacter 10 designates generally a 1 18,, or the equivalent.

comm nio isaefiserieu n 371,207.

magnetizing structure-which preferably coin prises a' U-shapedmagnet,member lhrthe ends of the magnet member 1-1 having'a recetangular plate l2 securedto them by screws A rel t y l rge" 5 aperture1% formed in the rectangular plate 12 is co-axiallydi'sposed withrespectgto aperture 15 formed in the magnet member 11. 'Dispo'sedin theaperturel l is oneend.

of a pole piece 16 which is preferablyt'ubu- 6' lar inform projects intotheaperture 15. Disposed around the pole piece 16 is a ring 18. formedfrom non-magnetic material and mounted in a recess 24 formed in thering.18; is an annularpole piecei22 spacedfrom the pole piece 16 to providean annular mag-J V netic field. The annular pole piece is pref erablyfitted snug y n the p rtur l .Dis,- posed around the polepiece 161'sawinding; 23,,wher'eby the magnet member, the rec'- t ngul rp te l2edthe p0lep e n 22 may be magnetized. Obviously, the mag,- netizingcurrent maybe of such magnitude that the field between the pole piecesl6 and 22 will be relatively intense, the'magnetizing electriccurrentbeing derived from any suit;

able source, r H 4 e Disposed inthe annular magnetic field providedbetween the pole'pieces 16 and22 is an electrical conducton armature orwinding 26 adapted to be subjected to telephonic currents obtained-froma radio-receiving set, i or the like. The winding 26 is mounted upon anannular'member 27 which maybe; formed fromany suitable material, such aspaper, or a phenolic condensation product," Formed integral withtheannular meine ber27 is a conical flange 30 in which the apex I of aconicalmember 32, is seated, the conical member 32 being part of thediaphragm which is designated generally by reference character 38 andalso comprisesan annulus 34 attached tothei base of the conical portion32. The conical-portion 32 preferably formed from paper, or theequivalent, but the annulus 34is preferably formed from relativelyflexible leather, or the equivalent, The outer edge of the annulusgSl isprefer ablyrigidly secured to a ring 36 formed from sheet metal, or thelike, and the ringfi s sup- 100 ported by aplurality of arms 37 whichhave their outer ends spot-welded to the ring 36 and have their innerends secured to the magnet member 11 and to frame members 38 by screws40, or the e uivalent. The frame members 38 may be-o any suitableconstruc- 'tion and 'are'preferably formed'from sheet.

metal. .They are preferably provided with flanges 41 which may besecured to the mag.-

n'et'member i 11" and to the rectangularplate" 12 by theaforementioned'screws It will be noted that the apex of'the conicalportion 32 of the diaphragm 33 is apertured to accommodatearod43 whichpasses through the aperture and extends. into the conical portion.conical washer 44, the construction belng such Carried by the rod 43 isa that theedge of the conical washer 44 clamps the conical portion 32against the conical er against .the conical portion32.

flange30. A nut 45 screw-threaded upon the rod 43 maybe manipulated tourge the wash- A -portion of the rod 43 projects into tu- 25' bular polepiece 16 and is preferably enlarged in diameter to provide-an annularshoulder 46 against which a washer 47 is'positioned.

' A nut 48 screw-threaded upon the rod 43 clamps the central portion ofthe conical por- 7 with the interior surface of the hollow polehave-shown one of them in detail in Fig. 2.

piece 16'and the spiral spring members 50 and 51 are preferablycup-shaped and are preferably soldered v or otherwise. secured withinthe tube 53. 'The'metal from which the spiral spring members areformed'is preferably thin and relativelyfiexible. I

The-spiral spring members 50 and 51 are preferably identical inconstruction, and I It will be noted that each of the spiral springmembers is preferably formed from a sheet metal stamping, and thateach'is provided with a spiral slot 54 to provide a spring 56 havingaplurality'of convolutions, the constructlon being such that the springs56"do not exert sufficient tension on the diaphragm at anytime todistort the soundemitted therefrom. Thus, it is readily understood thatthe spiral springs 56'are not adapted to subject the diaphragm 33to-such tension, but that they-are 'adapted'to hold the conical portion32 of the diaphragm and the winding 26in neutral positions when theWinding 26 is not being subjected to telephonic currents. It might besaid that the springs 56 provide a restoring'force of a magnitudecorresponding to the magnitude of the electrical currents to which thewinding 26 is subjected-F A feature ofthe invention is the manner inwhich the spiral spring members 5Oand 51 hold the winding 26 and theannular member 27 in concentric relation with the pole pieces 16 and 22,it being well-known to those skilled in the art that because of therelatively small clearance allowedbetween the several'parts of the loudspeaker at this point, it isabsolutely. essential thatlthe winding anditssupport shall be 1 retained ,in concentric relation with respect :tothe'inner and outer pole pieces.- To prevent frictional engagementbetween the-fixed and moving parts, which frictional engagement woulddistort the sounds reproduced by the diaphragm'q 7 Another feature ofthe invention'is the construction of the magnet [members and pole piecesandthe manner inwhich ,they'are assembled' to remain in permanentalinement even when the speaker is subjected to rough handling,-etc. 1 a

type, the combination "with a magnet includingia tubular pole piece, ofacoil adapted-to 1. In a loud speaker 'of the electromagnetic move in the"magnetic field "of said magnet,

. and supporting means :forsaid coil compris ing flexible membersdisposed in said pole piece and extending outwardly-with respect to thelongitudinal axis of said coil,'said flexible members extending in anon-radial 'direc tion between said longitudinal axis and" a support,said flexible members being disposed substantially at right angles tothe direction 7 of movement of the coiland having a length greater thantheradialdistance between said longitudinal axis and said support.

' 2. In a si-gnal transmitting device, means including a tubularpolepiece form'ing a magnetic air'gap, a current-carrying, coil adaptedto move in said airgap, and a. yield ing support for said coilcomprising fiat strips of non-elastic flexible material] dis posed insaid pole piece and extending out wardly with resp'ectto thelongitudinalaxis of said coil, s'aidflat strips extending to fixedpoints, said strips being positioned with respect to the coil andfixedpoints soth at a twisting str'ain-w'illbe imposed" upon said;strips as the coil moves axially in said-gap.

In testimony whereof, lliave hereunto set my hand'this 17th day; of May,1929. 1

7 I JOSEPH SWALLOWV.

